First find the oxidation states of the various atoms:
<span>in Cr2O2 2- Cr @ +1; In NH3 N @ +3; in CrO3 Cr @ +3, N2 N @ 0 </span>
<span>Note that N gained electrons, ie, was reduced; Cr was oxidized </span>
<span>Now there is a problem, because B has NH4+ which the problem did not, and is not balanced, showing e- in/out </span>
<span>B.NH4+ → N2 </span>
<span>Which of the following is an oxidation half-reaction? </span>
<span>A.Sn 2+ →Sn 4+ + 2e- </span>
<span>Sn lost electrons so it got oxidized</span>
Oxygen is participating in non-polar covalent bond(s)
Oxygen forms 2 covalent bond.
This is because oxygen atoms have 6 valence electrons. This means that it has 2 lone pairs and 2 unpaired electrons that are shared in order to achieve octet configuration.
In this chemistry, the 2 lone pairs on the oxygen are not shared with any other atoms. Instead; they are assigned to the oxygen atom. The formal charge on the oxygen atom is zero. Oxygen's atomic number is 8 and is equal to the sum of the number of its valence and inner shell electrons.
<h3>What is non-polar covalent bonding?</h3>
Nonpolar covalent bonding is a kind of covalent bond in which the bonding electrons are shared equally between the two atoms.
Learn more about non-polar covalent bonding:
brainly.com/question/26056508
The correct answer is option 1. The mass of a proton is approximately equal to 1 atomic mass unit. They almost have the same mass with a<span> neutron </span>while the electron is about 2000 times lighter than the two. The three mentioned particles are the subatomic particles found in an atom.